bdfinlayson · August 29, 2015 14:24
diff --git a/gistfile1.js b/gistfile1.js
 // QUESTION: What is a closure in Javascript?

 // ANSWER: Javascript closures are inner functions 
 // that refer to variables in their outer function 

 // EXAMPLE:

 function whatNum () {
  var outerNum = 10;
  console.log('I am the outer function and I returned ' + outerNum)
  function sayNum () {
    console.log('I am the inner function and I returned ' + outerNum + ' because I can see my outer scope');
  }
  return sayNum ();
 }

 console.log(whatNum()); // outputs the value of outerNum in both the outer and inner functions, which is 10

 // Closures can also remember changes made to a variable's value in the closure's outer function.
 // This functionality will override the variable's initial value (in this case, 'Bryan').
 // But this functionality lets you retrieve the new value of the variable.
 // You can do this after it has been changed (in this case, it's changed to 'John').

 // EXAMPLE:

 function whatIsMyName() {
  var myName = 'Bryan';
  return {
    getName: function() {
      return myName;
    },
    setName: function(newName) {
      myName = newName;
    }
  }
 }

 var whatName = whatIsMyName();
 console.log('This is my old name ' + whatName.getName()) // myName at this point is Bryan
 whatName.setName('John')
 console.log('And this is my new name ' + whatName.getName() + ' and it reflects the earlier change I made to my outer variable.') // myName at this point is John


 // QUESTION: What does stateless HTTP protocol mean? What are cookies?

 // ANSWER: I wasn't sure what was meant by 'stateless' in this context, so I wanted to look it up after the interview. 
 // According to this StackOverflow article (http://stackoverflow.com/questions/13200152/why-say-that-http-is-a-stateless-protocol), 
 // 'stateless' refers to the fact that a server does not hold the 'state' of a user. Rather, servers require certain information, 
 // such as a user's cookie, before fulfilling a request, such as GET or POST. In this context, a server might store a session cookie's 
 // key for that user, and destroy it when the user logs out. About this last point, I got exposure to creating cookies 
 // for authentication purposes while doing Hartl Rails Tutorial Ed 2. A link to the repo on Github is here:
 // https://github.com/bdfinlayson/Hartl_Rails_Tutorial_Microblog_App


 // QUESTION: Give an example of hoisting in Javascript

 // ANSWER: I could have explained this a bit better by discussing the role of scope. When I have a method in the global scope, such as:

 var dayOfWeek = 'Tuesday'

 // I can access it within a function, like so:

 function whatDayIsIt1 () {
  console.log(dayOfWeek) 
 }

 whatDayIsIt1() // outputs 'Tuesday'

 // But if I redefine the variable at the bottom of the function, it will hoist the variable declaration to the top of the function's scope
 // this leaves our console.log to output a value of 'undefined', as shown below:

 function whatDayIsIt2 () {
  // the output is undefined because dayOfWeek is hoisted and implicitly declared at the top of the function as an undefined variable
  console.log(dayOfWeek) 
  var dayOfWeek = 'Wednesday'
 }

 whatDayIsIt2() // outputs 'undefined'

 // This unusual behavior is why it is always good to define your variables at the top of your functions:

 function whatDayIsIt3 () {
  var dayOfWeek = 'Wednesday'
  console.log(dayOfWeek) 
 }

 whatDayIsIt3() // outputs 'Wednesday'
	// QUESTION: What is a closure in Javascript?

	// ANSWER: Javascript closures are inner functions
	// that refer to variables in their outer function

	// EXAMPLE:

	function whatNum () {
	var outerNum = 10;
	console.log('I am the outer function and I returned ' + outerNum)
	function sayNum () {
	console.log('I am the inner function and I returned ' + outerNum + ' because I can see my outer scope');
	}
	return sayNum ();
	}

	console.log(whatNum()); // outputs the value of outerNum in both the outer and inner functions, which is 10

	// Closures can also remember changes made to a variable's value in the closure's outer function.
	// This functionality will override the variable's initial value (in this case, 'Bryan').
	// But this functionality lets you retrieve the new value of the variable.
	// You can do this after it has been changed (in this case, it's changed to 'John').

	// EXAMPLE:

	function whatIsMyName() {
	var myName = 'Bryan';
	return {
	getName: function() {
	return myName;
	},
	setName: function(newName) {
	myName = newName;
	}
	}
	}

	var whatName = whatIsMyName();
	console.log('This is my old name ' + whatName.getName()) // myName at this point is Bryan
	whatName.setName('John')
	console.log('And this is my new name ' + whatName.getName() + ' and it reflects the earlier change I made to my outer variable.') // myName at this point is John


	// QUESTION: What does stateless HTTP protocol mean? What are cookies?

	// ANSWER: I wasn't sure what was meant by 'stateless' in this context, so I wanted to look it up after the interview.
	// According to this StackOverflow article (http://stackoverflow.com/questions/13200152/why-say-that-http-is-a-stateless-protocol),
	// 'stateless' refers to the fact that a server does not hold the 'state' of a user. Rather, servers require certain information,
	// such as a user's cookie, before fulfilling a request, such as GET or POST. In this context, a server might store a session cookie's
	// key for that user, and destroy it when the user logs out. About this last point, I got exposure to creating cookies
	// for authentication purposes while doing Hartl Rails Tutorial Ed 2. A link to the repo on Github is here:
	// https://github.com/bdfinlayson/Hartl_Rails_Tutorial_Microblog_App


	// QUESTION: Give an example of hoisting in Javascript

	// ANSWER: I could have explained this a bit better by discussing the role of scope. When I have a method in the global scope, such as:

	var dayOfWeek = 'Tuesday'

	// I can access it within a function, like so:

	function whatDayIsIt1 () {
	console.log(dayOfWeek)
	}

	whatDayIsIt1() // outputs 'Tuesday'

	// But if I redefine the variable at the bottom of the function, it will hoist the variable declaration to the top of the function's scope
	// this leaves our console.log to output a value of 'undefined', as shown below:

	function whatDayIsIt2 () {
	// the output is undefined because dayOfWeek is hoisted and implicitly declared at the top of the function as an undefined variable
	console.log(dayOfWeek)
	var dayOfWeek = 'Wednesday'
	}

	whatDayIsIt2() // outputs 'undefined'

	// This unusual behavior is why it is always good to define your variables at the top of your functions:

	function whatDayIsIt3 () {
	var dayOfWeek = 'Wednesday'
	console.log(dayOfWeek)
	}

	whatDayIsIt3() // outputs 'Wednesday'